• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.265-268
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• 2009

The purpose of this study is to analyze the casual relationship among Housing Transaction Index, Jeonse Rental Index and Interest Rate. To analyze the influence of interest rate in more detail, CD Interest rate and Spread are used as variables. Granger Casualty Test is used as a analysis tool, As a result, Spread is the cause variable of the Housing Transaction Index and the Housing Transaction Index is the cause variable of the CD Interest Rate. And also, CD Interest rate influences the Jeonse Rental Index and the Jeonse Rental Index has influence on the other variables.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.1-7
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• 2008

Recent trends of development in small size gasoline engines are both to have higher compression ratio for the purpose of improved fuel consumption and to advance spark timing up to DBL in a low to mid engine speed region for a good acceleration performance of vehicles. However, there occurs the deviation of corrected engine torque results during engine performance test on dynamometer because test conditions influence the onset of knock. Therefore, this research shows the test deviation of corrected engine torque decreases when knock correction rate is used.

• Transactions of Materials Processing
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• v.3 no.2
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• pp.215-228
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• 1994

The purpose of this paper is to pursue a general method to determine both the flow stress of a material and the friction factor by ring compression test. The materials are assumed to obey the expanded n-power hardening rule including the strain-rate effect. Ring compression is simulated by the rigid-plastic finite element method to obtain the database used in determining the flow stress and friction factor. The Simulation is conducted for various strain hardening exponent, strain-rate sensitivity, friction factor, and compressing speed, as variables. It is assumed that the friction factor is constant during the compression process. To evaluate the compatibility of the database, experiments are carried out at room and evaluated temperature using specimens of aluminum 6061-T6 under dry and grease lubrication condition. It is shown that the proposed test method is useful and easy to use in determining the flow stress and the friction factor.

• Nuclear Engineering and Technology
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• v.30 no.5
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• pp.424-434
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• 1998

RELAP5/Mod3.1 code was assessed with the semiscale experiment S-NC-3, and S-NC-4, which simulated the two-phase natural circulation and reflux condensation for the SBLOCA of PWR, respectively . Test S-NC-3 and S-NC-4 calculation results showed that RELAP5/Mod3.1 quite well describes the influence of steam generator secondary side heat transfer degradation on both two-phase natural circulation and reflux condensation. A comparison between the calculated and measured two-phase mass flow rate in test S-NC-3 shows good agreement for primary mass inventory more than 92%. And RELAP5/Mod3.1 have a good mass flow rate prediction capability for the transient such as S-NC-4 except some flow oscillations. The reflux flow rate for S-NC-4 test is under predicted, and the overall results verify that the correct prediction of the reduced liquid level appears to be required for the correct calculation of the overall phenomena.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.723-730
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• 2006

In the electrical railway, the tension ascension of contact wire is essential to speed up of train and current collection performance of catenary largely depends on the tension. The tension variation rate of the tensioning device used in existing line limits within 5%, and the tension variation rate of the spring-type tensioning device installed at the section where tensioning length is short bounds within 15%. So it is urgent for us to localize it for high speed line, which the tension variation rate is limited within 3%. Therefore in this study, a pulley-type tensioning device for high speed line is developed. To verify the performance of developed device, a performance test, overload test and failure test is carried out under the code of the Kyung-Bu High Speed line. And it is secured durability performance through a fatigue test.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.11
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• pp.124-131
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• 1996

The dynamic material property of Mn-B ally high-strength steel is investigated through the rod impact test which is one of simple test methods for the analysis of the material behavior under high-strain-rate. Rod impact test is performed to produce the deformed shape of rod and analyzed by the one-dimensional theory based on conservation law and the two-dimensional hydrocode AUTODYN-2D. The dynamic yield stress is determined and compared with the static yield stress to investigate the strain-rate sensitivity of Mn-B alloy high-strength steel.

• Journal of Korean Society of Rural Planning
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• v.13 no.2
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• pp.85-92
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• 2007

This study aims to show how the urbanization of Korea has progressed for the last three decades, what its characteristics are, and how rural land use has changed by the national and district(cities and counties) level. The land use changes accompanying to the urbanization is analyzed through 3 indicators such as urbanization rate, the rate of cultivated and forest land and the rate of urbanized area. The statistical data are 30 years from 1976 to 2005 for time series analysis by the national level, and are for the two years of 1995 and 2005 by the district level. The relationship between urbanization and land use changes in the national level is analyzed using statistical analysis(Correlation Analysis). In order to analyze the dynamic and spatial urbanization and land use changes effectively in the district level, Z-score, Paired T-test, Correlation Analysis, Analysis of Variance and Chi-squire Test are used. The results show negative correlation between urbanization rate and the rate of cultivated and forest land, and positive correlation between urbanization rate and the rate of urbanized area respectively. In the aspect of the change of urbanization rate, four categories are examined. In addition, four types are characterized on the basis of the rate of cultivated and forest land and the rate of urbanized area between 1995 from 2005.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.8 no.2
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• pp.178-185
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• 1998

In order to evaluate and improve the performance of local exhaust ventilation systems for two TCE degreasing (A, B) and two electroplating (C, E) and one acid dipping & plating (D) operations located in Kimhae, the performance test was conducted with trace gases and a thermal anemometer (Kanomax 24-6111, Japan). For the inadequately designed systems, the improvement and redesigns in compliance with recommendation by ACGIH was suggested. The results of performance test for each system are as follows; 1. System of Workplace A was generally well-designed. Actual exhaust air flow rate was in excess of 68% above the recommended standard exhaust air flow rate. 2. System of Workplace B was very well-designed and completely enclosed. 3. All systems of Workplace C including hoods were poorly-designed and actual exhaust air flow rates were insufficient for open tanks. All systems should be upgraded according to ACGIH recommendations. 4. Supply and exhaust air flow rate of push-pull exhaust systems in Workplace D should be greatly increased. The width of flange of dipping tank hood should be increased with the value suggested. 5. System of Workplace E was well-designed. Actual exhaust air flow rate was in excess of 54% above the required.

• The KSFM Journal of Fluid Machinery
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• v.14 no.1
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• pp.42-47
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• 2011

Measurement uncertainty analysis of fuel flow using turbine flowmeter was performed for the case of altitude engine test. SAE ARP4990 was used as the fuel flow calculation procedure, as well as the mathematical model for the measurement uncertainty assessment. The assessment was performed using Sensitivity Coefficient Method. 11 parameters involved in the calculation of the flow rate were considered. For the given equipment setup, the measurement uncertainty of fuel flow was assessed in the range of 1.19~1.86 % for high flow rate case, and 1.47~3.31 % for low flow rate case. Fluctuation in frequency signal from the flowmeter had the largest influence on the fuel flow measurement uncertainty for most cases. Fuel temperature measurement had the largest for the case of low temperature and low flow rate. Calibration of K-factor and the interpolation of the calibration data also had large influence, especially for the case of very low temperature. Reference temperature, at which the reference viscosity of the sample fuel was measured, had relatively small contribution, but it became larger when the operating fuel temperature was far from reference temperature. Measurement of reference density had small contribution on the flow rate uncertainty. Fuel pressure and atmospheric pressure measurement had virtually no contribution on the flow rate uncertainty.

• Journal of the Korean Society of Safety
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• v.32 no.3
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• pp.28-33
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• 2017

In this study, the composite material of expandable graphite was made to the material development for improving such as a composite material of the sandwich panels or material properties of a fire door and was tested by the ISO 1182, ISO 5660-1(Cone calorimeter Method). For the test, the composite material of expandable graphite, what the expandable graphite ratio was increased by respectively 0g~30g, was classified A1,A2, A3, A4, and made to the test specimens. Through cone calorimeter test, peak heat release rate(HRR) and total heat release(THR), expanded thickness and expansion rate of each composite material of expandable graphite, and fire prone crack and mass loss rate after burning was measured. Thus, the effect of the addition of the expandable graphite and whether is suitable for reference as a fire retardant, was analyzed. Consequently the correlation of THR and fire retardant performance rate was confirmed.